Prevention of foaming in steam generation



Patented Jan. 1, 1952 UNITE STATES signors to National Aluminate Corporation, Chicago, 111., a corporation of Delaware No Drawing. Ap lication March 27, 1942,

Serial No. 436,495 7 The present invention relates to antifoaming compositions which are used in-steam boilers and similar steam generators, evapora'tors, etc., to overcomethe tendency of the water therein to foam and henceto bring about thepriming of the steam generator or the like.

One of the objects of the present invention relates t'o a liquid for the generation of steam in steam generators and comprising water containing a very smallamount of complex condensation products derived by the reaction between certain acylated polyamines, acylated hydrazines, etc. with coupling ag'ents productive of polyacylated products as more fully described hereinbelow; When water containing small amounts of these substances is heated to the boiling point in a steam boiler or other generator, being thereby evaporated, the concentration of solids therein will not'bring about excessive foaming and the resu'ltingpriming, these compounds being substantially nonvolatile with the steam and stable, so that they will be retained by the water and neither they nor their decomposition products will appear in the steam and the resulting condensa non thereof.

It is well known in the operation of steam'boilers, such as in electric power plants, railroad loco-1 motives and the like,'or in evaporators, that the water therein, even though initially it shows very little tendency to foam, will, when the amount of total solids therein approaches a relatively high concentration, develop a very decided tendency to foam. When this occurs, considerable-quanti ties of water are physically carried out of the boilers or evaporators with the steam, thus appeer ng in the steam lines and in the eventual condensate. Such priming has many disadvan tages because it tends to contaminate the steam lines, to plug or corrode the valves, and under serious conditions may even impair the cylinders and pistonrods of the Steam engines, or the impelle'r blades of turbines in which'the steam is used-for the generation of power. Attempts have been made in the past to control this foaming, either by excessive blowdown of the boilers or by the injection thereinto of such materials as cast'or Oil, tallow, and the like. While these fatty materials have somesmall degree of efliciency; they are, on the other hand, 'quite deficient in that they introduce new difiiculties which, in some instances, are worse'than the conditions they are intended to cure. In the first place, these fatty 12 Claims. (01. 252-321) 1 methods.

acids or glycerides are unstable under the conditions existing in the boilers, particularly as the pressure and temperature increases, the high temperatures leading to rapid decomposition of the glycerides, which, if anything, will .tend to in crease the foaming and priming difficulties. Furthermore, in many instances certain of the decomposition products thus produced, or sometimes even the materials themselves, have a definite volatility with steam and will, therefore, steamdistil out of the boilers, thus appearing in the steam and in the condensate. This, of course,- is also very undesirable. Furthermore, such types of antifoaming agents usually have to be employed in relatively large quantities, adding not only to the expense but alsov to the inconvenience'of oper ating' the steam generators;- and those which have a 'tendencyto decompose do so quite rapidly, and hence their effectiveness is of short duration, which therefore'necessitates the continual charging into the boilers or other steam generators of considerable amounts of these older antifoam'ing agents. difllcult to use because the amounts in which they are efiicacious are very critical, and any overdosage usually aggravates the difficulty instead of curing it. I

It has now been found that compounds of th nature already hereinabove indicated are highly efiicient antifoaming and antipriming agents for use in steam generators. These compounds can be considered as being polyacylated polyamines, which can be obtained by a'number of different Thus it is possible to couple monoacylalkylenediamines, 'monoacylhydrazines, monoacylarylenediamines, acyl'ated polyalkylenepolyamines, monoacylpiperazines and the like by means of, for example, dichloroacetone, formaldehyde and itspolymers, dichloroethylene (1,2-dichloroethan'e) or. combinations of a dihalide plus a polyamine concurrently.

Particularly useful products may be obtained by coupling-two or more already acylated polyamines with (a) certain organic dihalides, (-b) formaldehyde or its-polymers, (c) an alkylene dihalide and an alkylenepolyamine concurrently, or (d) an acylated hydrazine with s-dichloroacetone, formaldehyde, etc.

Materials coming within the scope of the pres ent invention produced by the coupling of diacyl polyalkylenepolyamines, may be represented by the following probable general formula:

Moreover, such antifoaming agents are wherein X is an aliphatic hydrocarbon radical which may contain one or more double bonds and may contain hydroxyl groups, that is, X-CO and -OCX are the acyl radicals of aliphatic or hydroxyaliphatic acids; Y may be the alkylene or arylene residue of a polyamine; and Z is an alkylene group which may contain a carbonyl group, one or more amino nitrogens or an ether linkage. In case of hydrazine derivatives the constituent Y will obviously be absent. Hydrazine is to be considered as a type of polyamine for the present purpose. v

I It is to be understood that the formulas recited in the claims are probable in that the formulas given are believed to be possessed by the compounds disclosed, or whose method of preparation is disclosed in this specification.

Some specific examples of the above products are those resulting from the condensation of about two mols of dioleyldiethylenetriamine and one mol of ethylene dichloride; (2) the product resulting from the condensation of about 2 mols of dilauryldiethylenetriamine with one mol of ethylene dichloride; (3) the product resulting from the reaction of about one mol of dilauryldiethylenetriamine and one mol (100% excess) of formaldehyde in the presence of hydrogen chloride; (4) the product resulting from the reaction of dioleyldiethylenetriamine and an excess of formaldehyde, in the presence of sulfuric acid; (5) the product resulting from the condensation of about 3 parts of dioleyldiethylenetriamine and 2 parts of a complex amine-containing dihalide formed by the preliminary condensation of equal parts of triethylenetetramine and ethylene 'dichloride; and (6) the product resulting from the concurrent reaction of about one mol of ethylene dichloride and about one mol of diethylenetriamine with one mol of dioleyldiethylenetriamine.

It has been found that an important factor in determining the efliciency of these materials as antifoam agents is their total molecular weight. Thus, where it is necessary to use relatively long acyl radicals in a derivative carrying only a few such groups, it is suflicient to use only one or two heavy acyl groups in a derivative that also bears several shorter acyl radicals, e. g., acetyl. In general it can be said that if the derivative contains at least about 30 carbon atoms, it will be of value. An increase in the number of carbon atoms over this figure generally results in an increased efficiency, although the two varriables are not directly related. A further advantage to be gained by operating under several of the methods of the present invention, wherein the alkyleneamine groups of the product are multiplied, is that this type of condensation products usually is readily dispersible in water, and thus may be simply employed, or may require very little of an auxiliary dispersing agent.

The following examples are intended to illustrate typical preparations within the scope of the present invention, but are not to be construed as limiting the invention beyond the appended claims.

1 Example 1.--15.7 grams (0.05-mol) of monostearylhydrazine is condensed with 3.2 grams (0.025 mol) of s-dichloroacetone at 150-160 C. for one hour with stirring.

Example 2. -15.'7 grams (0.05 mol) of monostearylhydrazine is condensed with 3.2 grams (0.025 mol) of 1,3-dichloro-2-propanol at 150- 160 C. for one hour with stirring.

Example 3.-15.7 grams (0.05 mol) of monostearylhydrazine is condensed with 1.501 grams (0.05 mol, 100% excess) trioxymethylene at 150- 160 C. for one hour with stirring.

Example 4.1.6333 grams (0.01666 mol) of ethylene dichloride is carefully weighed out into a small flask. 21 grams (0.0333 mol) of dioleyldiethylenetriamine is added and the flask is fitted with a Hopkins reflux condenser. The mixture is warmed on the steam cone for 24 hours, and

hours with stirring. The product is a soft, brown wax.

Example 7 .Dioleyldiethylenetriamine is heated at l160 C. with an excess of 40 percent formaldehyde and stirred for 3 hours. The produtes.

uct is a soft paste-like wax. This wax is treated with its weight of concentrated sulfuric acid sp. gr. 1.84) at C. The material immediately condenses to form a black, lumpy product.

' Example 8.-1'l grams of triethylenetetramine is mixed with 1'7 grams of ethylene dichloride .and the flaskis fitted with a reflux condenser.

The mixture is warmed until the reaction is initiated and then cooled externally to moderate the violence of the reaction. After the preliminary reaction has subsided, the compound is stirred at 170-175" C. for 4 hours. Eight grams of the polymer thus obtained above and 0.1 gram of potassium hydroxide are added to 12 grams of dioleyltriethylenetetramine and stirred at C. for 4 hours. The resulting product is completely dispersible in water and has excellent antifoam characteristics.

Example 9.63.1 grams (0.1 mol) of dioleyldiethylenetriamine is placed in a 200 cc. 3-necked round-bottomed flask fitted with a mechanical stirrer and two dropping funnels. funnel is charged with 10.5 grams (0.102 mol) of diethylenetriamine, and the other with 11.9 grams (0.12 mol) of ethylene dichloride. The flask is heated by an oil bath at a temperature of ISO-160 C. The stirrer is then started and the dropping funnels so adjusted that the addition of both liquids is completed during 15 min- The reaction mixture is stirred at 150 C. for 5 minutes longer to complete the reaction.

Example 10.--132 grams (0.282 mol) of dilauryldiethylenetriamine is condensed at 150- 160 C. with 29 grams (0.282 mol) of diethylene- One dropping.

i ftriamine and 28 grams (0.282 :in'ol) of ethylene dichloride for one hour with stirring; The light brown wax obtained "by this method is a very good antifoani material.

Example 1'1.-'--4;95 grams of ethylenedichloride is added dropwise during twenty minutes to 15.7

grams of monostearylhydrazine atl50-160" C. The resulting mixture was then stirred at this temperature for one'hour to complete the re- 7 action.

Example 12. 9.0 grams of mono'stear'ylhydrazine is condensed with 0.75 grams of trioxymethylene at 150-160 6., while stirring for one hour.

The product is a brown wax.

Example 13.9.0 grams of monost'earylhydrazine is condensed with 1.6 grams of s-dichloroacetone at '150-160 C. for one hour. The prod-- not is abrownwax.

The compounds described in the above examples, while they differ somewhat from each other in th'e'ir' relative eilicie'ncy as antifoaming materiaL-are all serviceable as such. Many of them are readily dispersiblein water, so that they need merely be dispersed in the water which is to be rendered nonfoaming under boiler service conditions. In the case of some of the compounds, these may be dispersed by emulsification, and the emulsions thus obtained may then be introduced by suitable feeding means into the boiler or into the feed water entering the same. n a

The amounts of the above-mentioned compounds which are required are extremely small, and general one grain per gallon is ample. For many purposes, however, amounts as little as 4 b grain per gallon in "the feed'water will still give valuable results, and the amounts may be even further reduced. Depending of course upon the degree of concentration of solids, the dosage may be varied, but one grain per gallon is about as much as would ever have to be used even under serious conditions, and for many purposes A grain per gallon and even less can be used. The process is particularly effective at pressures of about 250 pounds per square inch.

The introduction of the antifoaming compounds of the present invention into the boiler may be accomplished in a number of ways. Thus, the antifoaming compositions may be dispersed or physically mixed with, say, sodium carbonate or some other material used for treatin the boiler water and pumped with the feed water into the boiler by means of either an injector or a feed water pump. The compounds may also be dissolved in suitable organic Water-miscible solvents such as alcohols, others, ketones, etc. and introduced in small measured amounts into the feed water entering the boiler. Suitable mechanical measuring devices which will periodically or continuously inject the required dosage of the antifoaming compounds intothe feed water may be used, so that the introduction will be more or less in proportion to the steam consumption to which the steam generator is subjected. The invention therefore is not to be limited by the manner of introduction of the antifoaming composition but rather is to be construed in the terms of the hereunto appended claims.

We claim:

1. A method of generating steam which comprises boiling, under superatmospheric pressure conditions, water containing an amount of total dissolved solids tendin to produce foaming and priming and a quantity of the product of condensation of about 2 mols of monostearyl hydrazine with about 1 mol of s-dichloroacetone, said 'quantltybei ng sufficient to substantially inhibit solved 'solids tending to produce foaming and priming and a quantity of a condensation product of about 2 mole of monostearyl hydrazine and 1 mol of s-dichloroacetone, said quantity bei'n'g suflicie'nt to substantially inhibit said foaming and priming.

3. A method of generating steam which comprises boiling, under superatmospheric pressure conditions, watercontaining an amount of total dissolved solids tending to produce foaming and priming and a quantity of a wax-like coupled partially acylated polyamine in which one mol of a partially acylated polyamine is coupled toanother mol of a; similar partially acylated polyamine through a group from the class consisting of; simple alky'leiie radicals, 'alkylene radicals containing a carbonyl group and alkylene radicals containing at least one amino nitrogen, no alkylene radical in said group containing more than 3 carbon atoms, said coupled partially acylated polyamine containing at least 30 carbon atoms, and said quantity being sufiicient to substantially inhibit said foaming and priming.

4. A liquid for the generation of steam, substantially devoid of foamin and priming tend-'- encies when heated to the boiling point, comprising water containing an amount of total dissolved solids tending to produce foaming and priming and a quantity of a wait-like coupled partially acylated polyamine in which one mol of a partially acylated polyamine is coupled to another mol of a similar partially acylated polyamine through a group from the class consisting of simple alkylene radicals, alkylene radicals containing a carbonyl group and alkylene radicals containing at least one amino nitrogen, no alkylene radical in said group containing more than 3 carbon atoms, said coupled partially acylated polyamine containing at least 30 carbon atoms, and said quantity being sufiicient to substantially inhibit said foaming and priming.

5. A method of generating steam which comprises boiling, under superatmospheric pressure conditions, water containing an amount of total dissolved solids tending to produce foaming and priming and a quantity of a condensation product as claimed in claim 3 wherein the partially acylated polyamine is monostearylhydrazine, said quantity being sufiicient to substantially inhibit said foaming and priming.

6. A liquid for the generation of steam substantially devoid of foaming and priming tendencies when heated to the boiling point comprising Water containing an amount of total dissolved solids tending to produce foaming and priming and a quantity of a condensation product as claimed in claim 4 in which the partially acylated polyamine is monostearylhydrazine, and said quantity being sufiicient to substantially inhibit said foaming and priming.

7. A method of generating steam which comprises boiling, under superatmospheric pressure conditions, water containing an amount of total dissolved solids tending to produce foaming and priming and a quantity of the product of condensation of about 2 mole of dioleyldiethylenetriamine and l' mol of ethylene dichloride, said quantity being sufiicient to substantially inhibit said foaming and priming.

" 8. A liquid for the generation of steam substantially devoid of foaming and priming tend encies when heated to the boiling point comprising water containing an amount of total dissolved solids tending to produce foaming and priming and a quantity of the product of condensation of about 2 mols of dioleyldiethylenetriamine and 1 mol of ethylene dichloride and said quantity being sufficient to substantially inhibit said foaming and priming.

9. A method of generating steam which comprises boiling, under superatmospheric pressure conditions, water containing an amount of total dissolved solids tending to produce foaming and priming and a quantity of the product of condensation of about 2 mols of dilauryldiethylenetriamine with about 1 mol of ethylene dichloride, said quantity being sufficient to substantially inhibit said foaming and priming.

10. A liquid for the generation of steam substantially devoid of foaming and priming tendencies when heated to the boiling point comprising water containing an amount of total dissolved solids tending to produce foaming and priming and a quantity of the product of condensation of about 2 mols of dilauryldiethylenetriamine with about 1 mol of ethylene dichloride, and said quantity being sumcient to substantially inhibit said foaming and priming.

11. A method of generating steam which comprises boiling, under superatmospheric pressure conditions, water containing an amount of total dissolved solids tending to produce foaming and priming and a quantity of the product resulting from condensation of about 3 parts of dioleyldiethylenetriamine and 2 parts of a complex amine-containing dihalide formed by the preliminary condensation of equal parts of triethylene tetramine and ethylene dichloride, said quantity being sufiicient to substantially inhibit said foaming and priming.

12. A liquid for the generation of steam substantially devoid of foaming and priming tendencies when heated to the boiling point comprising water containing an amount of total dissolved solids tending to produce foaming and priming and a quantity of the product resulting from the condensation of about 3 parts of dioleyldiethylenetriamine and 2 parts of a complex amine-containing dihalide formed by the preliminary condensation of equal parts of triethylene tetramine and ethylene dichloride, and said quantity being suificient to substantially inhibit said foaming and priming.

- PAUL G. BIRD.

ARTHUR L. JACOBY. ROBERT W. KELL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name a Date 1,892,857 Spellmeyer Jan. 3, 1933 1,924,698 Neelmeier et al. Aug. 29, 1933 2,074,380 Flett Mar. 23, 1937 2,304,805 Denman Dec. 15, 1942 2,328,551 Gunderson Sept. '7, 1943 2,345,632 Robinson et al. Apr. 4, 1944 

3. A METHOD OF GENERATING STEAM WHICH COMPRISES BOILING, UNDER SUPERATMOSPHERIC PRESSURE CONDITIONS, WATER CONTAINING AN AMOUNT OF TOTAL DISSOLVED SOLIDS TENDING TO PRODUCE FOAMING AND PRIMING AND A QUANTITY OF A WAX-LIKE COUPLED PARTIALLY ACYLATED POLYAMINE IN WHICH ONE MOL OF A PARTIALLY ACYLATED POLYAMINE IS COUPLED TO ANOTHER MOL OF A SIMILAR PARTIALLY ACYLATED POLYAMINE THROUGH A GROUP FROM THE CLASS CONSISTING OF SIMPLE ALKYLENE RADICALS, ALKYLENE RADICALS CONTAINING A CARBONYL GROUP AND ALKYLENE RADICALS CONTAINING AT LEAST ONE AMINO NITROGEN, NO ALKYLENE RADICAL IN SAID GROUP CONTAINING MORE THAN 3 CARBON ATOMS, SAID COUPLED PARTIALLY ACYLATED POLYAMINE CONTAINING AT LEAST 30 CARBON ATOMS, AND SAID QUANTITY BEING SUFFICIENT TO SUBSTANTIALLY INHIBIT SAID FOAMING AND PRIMING. 